Rosaceae: Rosoideae - achenes

BOT 360F - Families of Vascular Plants

Achenes are dry, indehiscent fruits (fruitlets) that in Rosaceae subfamily Rosoideae may develop enclosed by a fleshy hypanthium (arrow A, top row, right; in a hooked hypanthium in Agrimonia) or on an enlarged floral receptacle, as in Fragaria (arrow, bottom row, left). In both these cases the resulting fruit is an aggregate of achenes (all developed from the pistils of a single flower with an apocarpous gynoecium).

Rosa fruit - 15565 Bytes Rosa fruit - 11975 Bytes
Fragaria fruits - 13409 Bytes Top row, left; Rosa fruit in longitudinal section, achenes enclosed in fleshy hypanthium, R. Joos. Top row, right; Rosa fruit in longitudinal section (A, achene; S, styles filling hypanthium neck). Note that fruit has been occupied by insect larvae. Photo: R. C. Evans 1998 R. C. Evans. Bottom row, left; Fragaria virginiana fruits with achenes (arrow) on surface of enlarged receptacle.


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